Screening, Identification of a High-producing Cold-active Amylase Strain and Its Amylase Characterization
Exploitation of cold-active amylase resource had been a hotspot in functional enzyme research,in this study strains producing cold-active amylase were isolated from the frozen soil of Yangbark glacier,East Pamirs.Among them,the strain D5-2 with the highest amylase activity was identified as Pseudomonas sp.by16S rDNA sequence analysis.The study on enzymatic properties showed that the optimum temperature and pH for catalytic activity was 25 ℃ and pH 6.5,respectively.And the thermal stability of the enzyme was relatively poor,having incubated the enzyme at 40 ℃ for 1 h,the enzyme decreased sharply,retained 23％ of its original activity incubated in 70 ℃,The cold-adaptable amylase had high activities between pH 5.5 and 8.0.The amylase activity was activated by Mg2+ and Mn2+,and was inhibited by ethylene diamine tetraacetic acid (EDTA),Fe2+ and Na+,especially.EDTA could affect the enzyme activity significantly.The result indicated Pseudomonas sp.D5-2 was a cold-active amylase producing strain which showed application potential,deserving to be further research.
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